JP3544368B2 - Standby control method and mobile device in mobile communication system - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a standby control method in a mobile communication system, and more particularly, to a standby control method in which a mobile station can wait in a zone where the mobile station should originally wait even if a zone formed by a base station is not ideal in the mobile communication system. About.
[0002]
In addition, the present invention relates to a mobile station capable of waiting according to such a standby control method.
[0003]
[Prior art]
2. Description of the Related Art Conventionally, for example, in a mobile communication system of a PDC (Personal Digital Cellular) system, a mobile station, while waiting, loses frame synchronization in a control channel received from a base station, deteriorates a reception level, and a bit error rate (BER: Bit Error). Rate) When deterioration is detected, the control channel is recognized as a defective channel, and the control channel is shifted to another control channel.
[0004]
[Problems to be solved by the invention]
When the transition control to another control channel is performed as described above, the transition control is performed without any problem if the zone formed by the base station is ideally formed, but the zone of the base station is ideally formed. Otherwise, the mobile station may receive radio waves from a distant base station with good visibility. In such a case, the mobile station waits in a zone that should not normally wait, and cannot perform communication with a base station that should perform communication. FIG. 7 is a schematic diagram showing such a problem. As shown in the figure, if the mobile station 100 determines that the reception level of the control channel from the base station B220 and the BER are better than that of the base station A210, even if the base station is located far away, B220 is regarded as a communication partner, and a call to base station B220 is repeatedly attempted without shifting to another zone. However, since the zone of the base station B220 is not the zone to which the mobile station 100 should originally belong, the call from the mobile station 100 fails, and as a result, the call connection rate (= calling success rate) decreases.
[0005]
The present invention has been made in view of the above-described problems, and an object of the present invention is to prevent a decrease in a call success rate even when a zone formed by a base station is not ideal. An object of the present invention is to provide a standby control method in a mobile communication system.
[0006]
It is another object of the present invention to provide a mobile device capable of performing standby control according to such a standby control method.
[0007]
[Means for Solving the Problems]
In order to solve the above problem, according to the present invention, as described in claim 1, a mobile station located in a zone formed by a base station has a reception quality of a control channel received from the base station that is predetermined. In the standby control method of selecting a control channel such that a standby state is established, the mobile station determines whether or not the control channel used for the outgoing call is defective based on the frequency of call failures. When the control channel is determined to be defective in the above determination , the mobile terminal shifts to another control channel and performs standby, and the frequency of the call failure is determined when the mobile station calls using a certain control channel. It indicates the number of consecutive call failures, and the number of call failures is configured to be set for each cause of the call failure .
[0008]
According to such a standby control method, the mobile station recognizes a control channel having a high frequency of call failures as a bad channel, so that the mobile station is in a zone where it should not wait, so that the mobile station can communicate with a desired base station. It can be determined that communication is not possible. When the mobile station recognizes the called control channel as a bad channel, it shifts to another control channel and performs standby, so that even if an area is not ideally formed, a base station that is not a communication partner as in the past. Call can be suppressed as much as possible, so that a decrease in the call success rate can be prevented. Further, since the control channel that has failed to make a call consecutively a certain number of times is recognized as a defective channel, it is possible to realize a rational transition to another control channel. Further, the timing of transition to another control channel can be controlled for each call failure cause.
[0012]
From the viewpoint that the recognition of a bad channel can be performed more accurately, the present invention provides a mobile station located in a zone formed by a base station, the mobile station receiving the control signal from the base station , as described in claim 2. In the stand-by control method for selecting a control channel having a predetermined channel reception quality and performing standby, the mobile station determines that the control channel used for the call is defective based on the frequency of call failures. It is determined whether or not the control channel is defective.If the control channel is determined to be defective, the mobile terminal shifts to another control channel and waits for a call. Is configured to use a conditional probability representing the success rate of the next call when the call is made.
[0013]
In such a standby control method, a conditional probability representing the success rate of the next call when a call failure occurs is used instead of the frequency of the call failure, so that a likely call failure cause Can be specified stochastically. As a result, the recognition of the defective channel can be performed more accurately.
[0014]
Further, from the same viewpoint as in claim 2 , according to the present invention, as set forth in claim 3 , in the standby control method, the conditional probability can be obtained for each call failure cause. .
[0015]
From the viewpoint can be performed accurately and reasonably transition to another control channel, the present invention is, as described in claim 4, the waiting in the control method, the conditional probability of a value obtained as described above Is configured to shift to another control channel and perform standby when is less than a predetermined threshold.
[0016]
According to such a standby control method, since a certain threshold value is set for the conditional probability for each call failure cause, the transition to another control channel can be performed accurately and rationally.
[0017]
From the viewpoint of allowing improved area quality, the present invention is, as described in claim 5, said in the standby control method, the conditional probability value for each call failure reason obtained as described above Is stored as a log, and the stored log data is notified to the network of the upper station via the base station.
[0018]
In such a standby control method, the mobile device collects the value of the conditional probability for each call failure cause as a log, and notifies the collected log data to the network of the upper station. The telecommunications carrier can take measures to improve the area quality by using the log notified to the network.
[0019]
By obtaining positional information of the calling failure of the mobile station, from the viewpoint that it can help improve the area quality, the present invention is, as described in claim 6, in the standby control method, the mobile The mobile device is provided with a GPS (Global Positioning System) location information acquisition function, and when the mobile device fails to make a call, saves the location information at the time of the call failure as a log, and stores the saved log data as a base station. To notify the network of the upper station via the network.
[0020]
In order to solve the above problems, the present invention is, as described in claim 7, a mobile station reception quality of the control channel received from the base station performs standby select the control channel such that the predetermined A first defective control channel determining means for determining whether the control channel used for the outgoing call is defective based on the frequency of call failures, and the control channel is determined to be defective in the above determination First control channel shifting means for shifting to another control channel in the case where the first defective control channel determining means determines that the mobile station has made a call using a certain control channel. It represents the number of failures, and the number of call failures in the first failure control channel determination means is configured to be set for each cause of the call failure.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0022]
A mobile communication system to which a standby control method according to an embodiment of the present invention is applied is configured, for example, as shown in FIG.
[0023]
In FIG. 1, this mobile communication system is, for example, a PDC (Personal Digital Cellular) system and includes a mobile device 100, a base station 200, a switching device 300, and a public network 400. The mobile device (eg, mobile phone) 100 performs wireless communication with the base station 200 and connects to the public network 400 via the exchange 300 so that voice communication or non-call communication with another terminal (mobile phone or the like) can be performed. It has become.
[0024]
The mobile device 100 is configured, for example, as shown in FIG.
[0025]
In FIG. 2, the mobile device includes a radio unit 11, a voice processing unit 12, a control unit 13, a transmission state monitoring and log storage unit 14, and a display operation / transmission / reception unit 15. The radio unit 11 has a function of performing frequency conversion (down-conversion) on a radio signal from the base station 200 to perform demodulation processing, and a modulation process on a transmission signal from the audio processing unit 12 and frequency conversion (up-conversion). . The voice processing unit 12 voice-encodes the voice signal input from the display operation / transmission / reception unit 15 and sends it to the wireless unit 11, and decodes the received signal demodulated by the wireless unit 11. The received signal decoded by the audio processing unit 12 in this way can be heard by the display operation / transmission / reception unit 15 as audio. The control unit 13 has a function of instructing the wireless unit 11 on transmission / reception timing of a transmission signal and a reception signal. The transmission state monitoring and log storage unit 14 monitors the transmission state of the mobile device 100, and, for example, monitors whether the call to the base station 200 is successful.
FIG. 3 is a flowchart showing a processing procedure for shifting the control channel based on the number of call failures.
[0026]
When a call is made from the mobile device 100 in the standby state (S1) (S2), it is determined whether the call is successful (S3). If it is determined in this determination (S3) that the call is successful (successful in S3), the process returns to the standby state again. However, if it is determined that the call has failed in the above determination (S3) (failure in S3), the process proceeds to the next process, and the cause of the failure of the call is analyzed (S4). Causes of this call failure include, for example, TCH activation failure due to failure to reach an uplink signal or failure to pull in synchronization of a traffic channel (TCH). Here, description will be made on the assumption that the result of the analysis of the cause of failure in (S4) indicates that the call has failed due to "uplink signal failure". In the next (S5), it is determined whether or not the number of call failures due to “uplink signal failure” is continuously equal to or more than a specified number, and it is determined that the number of call failures is less than the specified number (S5). In the case of NO), the number of call failures due to “uplink signal failure” is incremented by +1 (= failure count processing) and stored (S7).
[0027]
On the other hand, if it is determined in the above determination (S5) that the number of call failures exceeds the specified number (YES in S5), the control channel used for the call is stored as a defective channel (S8), and then the level is set. The control is shifted to the control channel of the next level with reference to the table arranged in the order of (S9), and returns to the standby state.
[0028]
In this embodiment, when a mobile station fails to call a certain number of times (= the number of consecutive failures), the mobile station recognizes the control channel used for the call as a bad channel and shifts to another control channel. Therefore, it is possible to suppress a call to a base station that is not a communication partner. Therefore, the mobile station can stand by in the zone where it should wait even if an ideal zone has not been formed, so that it is possible to prevent a reduction in the call success rate. In addition, if the number of consecutive failures is set to a small value, it is possible to quickly suppress a call to a base station that is not a communication partner.
[0029]
FIG. 4 is a flowchart showing a processing procedure for shifting the control channel based on the failure probability of a call.
[0030]
As in the case of FIG. 3 described above, when a call is made from the mobile device 100 in the standby state (S11) (S12), it is determined whether the call is successful (S13). In the case of the present embodiment, the statistical processing based on this determination (S13) is performed by the transmission state monitoring and log storage unit 14. This statistical processing is performed, for example, in the following procedure. Hereinafter, description will be made with reference to FIG.
[0031]
In the determination of (S13), if the first call from the mobile device (using the control channel 11) succeeds (successful in S13), the "success" in the second line of the statistical processing table 1 shown in FIG. “O” indicating the success of the call is written in the “failure” field (S14). The “communication CH” field in the third row is a communication channel (communication CH) to which the process proceeds after the call processing by the control channel is normally performed. Here, “21” is assigned to the communication CH corresponding to the first call.
[0032]
On the other hand, when the call from the mobile device fails (failure in S13) (failure in the third call in this example), the “success / failure” field in the second line indicates “failure of the call”. "X" is written, and the cause of the call failure is analyzed in the next step (S15). Here, the cause of the failed call is abbreviated as “A”. When the analysis of the cause of failure is completed in (S15), the next call success rate (= S) under the condition that the cause of failure A (= A) has occurred in the next (S16), that is, the conditional probability Calculation of P (S | A) (unit:%) is performed (S16). Specifically, the conditional probability P (S | A) for the call after the cause of failure A is calculated each time (see FIG. 5B) as follows.
1) The first call after the cause of failure A succeeds, so P (S | A) is 100%
2) The second call after the cause of failure A succeeds, so P (S | A) is 100%
3) The third call after the cause of failure A succeeds, so P (S | A) is 100%
4) The fourth call after failure cause A fails, so P (S | A) is 75%
5) The fifth call after failure cause A fails, so P (S | A) is 60%
The conditional probability P (S | A) calculated as described above is compared with a threshold value (eg, 50%) each time it is calculated (S17). If it is equal to or greater than the threshold value (YES in S17), The failure cause analyzed in S15) is stored in the "failure cause" field of FIG. 5B (S20), and the process returns to the standby state. However, if it is determined in the above determination (S17) that the value is equal to or less than the threshold (NO in S17), the control channel that has made the call is stored as a bad channel (S18), and a table arranged in order of level is referred to. To the next level control channel (S19) and return to the standby state. The conditional probability calculated as described above is obtained for each call failure cause (in this example, the conditional probability is calculated based on the call failure cause A as an example).
[0033]
As described above, in this embodiment, when a call from a mobile device fails for a certain cause, the next call success rate (conditional probability) under the cause is sequentially calculated and compared with the threshold. You. Only when the value falls below the threshold value, the control channel used for originating the call is recognized as a bad channel and the control channel is shifted to another control channel. In the case of this example, the conditional probability is equivalent to obtaining the probability of the cause assuming that the call failed due to a certain cause, in other words, stochastically identifying the cause of the control channel failure. It is. For example, if the success rate of the next call after the failure caused by the failure cause A is low, it can be predicted that this is due to the influence of the failure cause A. By determining the conditional probability in this way, it is possible to specify the likely cause of the failure, and if a threshold value for the conditional probability is set for each call failure cause, the transition to another control channel can be performed accurately and reasonably. Can be done Also in this embodiment, as in the case of FIG. 3 described above, it is possible to suppress unnecessary calls to the base station that is not the communication partner, so that it is possible to prevent a reduction in the call success rate.
[0034]
FIG. 6 is a flowchart showing a control channel shift procedure when the processing in FIG. 3 and the processing in FIG. 4 are combined.
[0035]
In FIG. 6, the processes in (S21) to (S26) are the same as those in FIG. In this example, it is determined (S27) whether or not the number of samples (the number of samples n in FIG. 5B) necessary to calculate the above-described conditional probability P (S | A) is obtained (S27). Is less than the specified value (NO in S27), it is determined whether the number of call failures due to the failure cause analyzed in (S25) has failed continuously more than the specified number (S28). In the processing after this determination, the same processing as in the case of FIG. 3 is performed (S29 to S31).
[0036]
On the other hand, when it is determined in the above (S27) that the number of samples is equal to or larger than the specified value (YES in S27), the calculated conditional probability is compared with a threshold (S32). In the processing after (S32), the same processing as in the case of FIG. 4 described above is performed (S33 to S35).
[0037]
As described above, the process of shifting to another control channel in this embodiment is performed according to the processing procedure shown in FIG. 3 when the number of samples is small, and when the number of samples exceeds a specified value, the process shown in FIG. The processing is performed according to the procedure shown in FIG. By adaptively switching the processing of FIGS. 3 and 4 in this manner, it is possible to flexibly shift to another control channel. Also in this embodiment, as in the case of FIG. 3 described above, it is possible to suppress unnecessary calls to the base station that is not the communication partner, so that it is possible to prevent a reduction in the call success rate.
[0038]
Up to now, the embodiment in which the mobile station 100 recognizes the defective control channel based on the number of call failures and the probability of call failure and switches to another control channel has been described. The mobile device 100 stores the calculation result of the conditional probability for each call failure cause as a transmission history log (for example, FIGS. 5A and 5B), and stores the stored information in a network (for example, the exchange 300 or the like). Configuration) can be used to improve area quality. Conventionally, call processing information has been collected on the network side and the collected information has been used to improve the area quality. However, if the uplink signal from the mobile device 100 does not reach, the uplink signal does not reach the base station 200. Therefore, the call processing information cannot be collected on the network side. In addition, since it is not known where the mobile device is located and to which base station it is calling, the current situation is that area quality surveys are periodically conducted in the field to improve quality. there were. In the present invention, the outgoing call history log, that is, outgoing call failure information including which channel is defective for what cause is periodically transmitted to the network. At this time, if the mobile device is equipped with a GPS (global positioning system), which is a position measuring means, and the position information can be obtained by GPS, the position information when the call has failed is also stored as a history and notified to the network. . By acquiring call failure information and location information when a call fails, the carrier can improve the quality of the acquired information (eg, adjust the angle of the antenna so that an appropriate area is formed). Or increasing the number of lines if the line is insufficient).
[0039]
In the above example, the transmission state monitoring function of the mobile device 100 and the transmission state monitoring function of the log storage unit 14 are performed by the first failure control channel determination unit, the second failure control channel determination unit, the first control channel shift unit, and the second failure control channel determination unit. The statistic processing function of the part 14 corresponds to the statistic processing means, the conditional probability calculating means for each call failure cause, and the sample collecting means, and the log function of the part 14 corresponds to the log collecting means. Corresponds to log data notification means. Further, the means selecting function of the faulty control channel judging means of the control unit 13 corresponds to the first faulty control channel judgment applying means and the second faulty control channel judgment applying means.
[0040]
【The invention's effect】
As described above, according to the present invention as set forth in claims 1 to 13 , the mobile station sets the faulty control channel based on the number of call failures or the call failure probability (conditional probability for each call failure cause). Recognition and transfer to another control channel can suppress repetition of calling to a base station that is not a communication partner even when an ideal zone is not formed. As a result, it is possible to more reliably perform the standby in the zone where the standby should be performed, so that it is possible to prevent a decrease in the call success rate.
[0041]
Further, by storing the call failure probability as a log and notifying the log of the log, the communication carrier can use the information of the log to improve area quality.
[0042]
Further, in the case of a mobile device that can acquire GPS location information, location information when a call has failed is also saved as a log and notified to the network, which can be used to further improve area quality.
[0043]
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a mobile communication system to which a standby control method according to an embodiment of the present invention is applied.
FIG. 2 is a configuration diagram of a mobile device.
FIG. 3 is a flowchart showing a processing procedure for shifting a control channel based on the number of call failures.
FIG. 4 is a flowchart showing a processing procedure for shifting a control channel based on a call failure probability.
FIG. 5 is a diagram illustrating an example of a transmission history log.
FIG. 6 is a flowchart showing a control channel shift procedure when the processing in FIG. 3 and the processing in FIG. 4 are combined;
FIG. 7 is a diagram for explaining a conventional technique.
[Explanation of symbols]
Reference Signs List 11 Radio unit 12 Voice processing unit 13 Control unit 14 Transmission state monitoring and log storage unit 15 Display operation / transmission / reception unit 100 Mobile device 200, 210, 220 Base station 300 Switch 400 Public network

Claims (13)

In a standby control method in which a mobile station located in a zone formed by a base station selects a control channel such that the reception quality of a control channel received from the base station becomes predetermined and performs standby.
The mobile station determines whether or not the control channel used for the outgoing call is defective based on the frequency of the failure of the outgoing call. Go to the channel and listen ,
The frequency of the call failure represents the number of consecutive call failures when the mobile device makes a call using a certain control channel,
A standby control method in which the number of call failures is set for each cause of a call failure. In a standby control method in which a mobile station located in a zone formed by a base station selects a control channel such that the reception quality of a control channel received from the base station becomes predetermined and performs standby.
  The mobile station determines whether or not the control channel used for the outgoing call is defective based on the frequency of the failure of the outgoing call. Go to the channel and listen,
A standby control method using a conditional probability indicating a success rate of a next call when a call failure occurs, instead of the frequency of the call failure. The standby control method according to claim 2 ,
A standby control method for determining the conditional probability for each call failure cause. The standby control method according to claim 2 ,
A standby control method in which when the value of the conditional probability obtained as described above falls below a predetermined threshold, the mobile terminal shifts to another control channel and performs standby. The standby control method according to claim 2 ,
A standby control method in which a value of the conditional probability for each call failure cause obtained as described above is stored as a log, and the stored log data is notified to a network of an upper station via a base station. The standby control method according to claim 2 ,
The mobile device is provided with a position information acquisition function by GPS (global positioning system), and when the mobile device fails to make a call, saves the position information at the time of the call failure as a log,
A standby control method for notifying the stored log data to a network of an upper station via a base station. In a mobile device that selects a control channel such that the reception quality of the control channel received from the base station is predetermined and performs standby,
  First bad control channel determining means for determining whether or not the control channel used for calling is bad based on the frequency of call failure;
  First control channel shift means for shifting to another control channel when the control channel is determined to be defective in the determination,
  The first faulty control channel determination means indicates the number of successive call failures when a mobile station makes a call using a certain control channel,
A mobile station in which the number of call failures in the first failure control channel determination means is set for each cause of a call failure. In a mobile device that selects a control channel such that the reception quality of the control channel received from the base station is predetermined and performs standby,
First bad control channel determining means for determining whether or not the control channel used for calling is bad based on the frequency of call failure;
First control channel shift means for shifting to another control channel when the control channel is determined to be defective in the above determination;
A statistical processing unit that uses a conditional probability indicating a success rate of the next call when a call failure occurs, instead of the frequency of the call failure. The mobile device according to claim 8,
The above-mentioned statistical processing means is a mobile station having calling probability-specific conditional probability calculating means for obtaining the conditional probability for each call failure cause. The mobile device according to claim 8 ,
Second defective control channel determining means for determining that the control channel used for calling is defective when the value of the conditional probability obtained as described above falls below a predetermined threshold value; And a second control channel shift unit that shifts to another control channel based on a determination result of the unit. The mobile device according to claim 8 ,
Log collecting means for storing the value of the conditional probability for each call failure cause obtained as described above as a log, and log data notifying means for notifying the stored log data to the network of the upper station via the base station And a mobile device having the same. The mobile device according to claim 8 ,
A position information acquisition unit that acquires position information by GPS (global positioning system);
A location information collecting means for storing, when a call fails, location information at the time of the call failure as a log;
Notifying means for notifying the stored log data to the network of the upper station via the base station,
Mobile device having a. The mobile device according to claim 7 or 9 ,
Sample collection means for collecting the success or failure of each call as a sample for each cause of failure; and, if the number of samples for each cause of failure collected by the sample collection means is equal to or greater than a prescribed value, the second failure control channel determination First defective control channel determination applying means for determining whether the control channel used for calling by the means is defective;
If the number of collected samples for each cause of failure is equal to or less than a specified value, the first failure control channel determination means determines whether the control channel used for calling is defective or not. A mobile device having a bad control channel determination application means.

Images